392
population) indicated Microcystis sp. (68 %),
Phormidium sp. (55 %) and so on.
(g) Quality status: The water colour of many
lakes is sometimes greenish, indicating
eutrophication mainly due to algal
blooms. c 23 % of lakes are said to be
affected by eutrophication (Chakrapani and
Ramakrishna Parama 1996 ). Moreover,
there have been frequent fi sh kills in the
lakes mainly due to pollution (Benjamin
et al. 1996 ). Further, there have been human
health problems particularly due to not very
good quality of municipal water supplies.
This may be due to degraded water quality
problems in few tanks, like the
Kamakshipalya and Kempambudhi tanks.
Further, the degraded water may also be
affecting the lives of aquatic biota, notably
the birds, fi sh, etc. (Krishna et al. 1996 ).
Further, on a long-term basis, in addition to
the loss of habitat, recreational, aesthetic
and economic values, such degraded water
may affect the overall ecosystem diversity,
productivity and stability, including loss of
the capacity of the wetlands to assimilate
nutrients, purify water, etc.
(h) Turbidity usually varies from 1.0 to 362.0
NTU with cleaner water recording 1.0–25.0
NTU while polluted water recording 70.0–
362.0 NTU. The high value is mainly due to
silt, suspended and organic matter and
autochthonous sources. These retard the
penetration of light and reduce rate of photosynthesis (Kiran and Ramachandra 1999 ).
(i) The pH generally ranges from 7 to 9.3 in
urban areas and 7.3–8.7 in non-urban areas.
Notably, Kamakshipalya usually record pH
of 6.0–6.6 (Kiran et al . 1999 ). pH values
>9.0 may be recorded at Yediyur, Puttenahalli
and Ulsoor tanks (Chakrapani and
Ramakrishna Parama 1996 ).
(j) The COD values usually range from 27 mg/l
(in unpolluted waters) to 621 mg/l (in polluted waters like Kamakshipalya) (Kiran
and Ramachandra 1999 ).
(k) The DO values generally range from
1.2 mg/l (in Kamakshipalya Lake) to
11.1 mg/l (in Ulsoor and Yediyur Lakes)
(Kiran et al. 1999 ). However, the recommended DO concentration for a productive
lentic body is said to be 8 mg/l (Wetzel
1973 ).
(l) The phosphate level generally ranges from
0.06 to 4.2 mg/l. Higher values are generally
seen in Kamakshipalya Lake (Kiran and
Ramachandra 1999 ).
(m) The nitrate concentration in the Bengaluru
lakes usually ranges from 0.1 to 2.7 mg/l.
However, the standard level of nitrate for
inland surface water is generally 0.1 mg/l
(NEERI 1988 ; Kiran and Ramachandra
1999 ).
(n) Dissolved solids generally range from 30 to
301 mg/l (in less polluted lakes, like
Bannergatta and Sankey) to 430.0–
1,024.0 mg/l (in highly polluted lakes, such
as Kamakshipalya and Yediyur).
(o) Concomitantly, the suspended solids ranged
from 52.2 to 278.3 mg/l (Kiran and
Ramachandra 1999 ).
(p) Amongst the metals, high values of iron and
lead were noted, while zinc and chromium
were found in traces (Kiran et al. 1999 ). The
permissible limit for iron is said to be
0.3 mg/l (NEERI 1988 ) for drinking water.
Iron, possibly, imparts bitter taste to water
above this value (Chakrapani and
Ramakrishna Parama 1996 ).
(q) In fi ne, investigations revealed that most of
the analysed parameters for the lakes in
Bengaluru (e.g. Ulsoor, Hebbal, Yediyur,
Kamakshipalya and Madivala) depicted
higher values than the permissible limits set
by Indian Standards for industrial and sewage effl uents discharge (IS 2490–1982).
Tanks
These lie at 300–750 m MSL, between 12° 30′
and 15°00′ N and 75°00′ and 78° 00′ E on the
plains of Karnataka. They extend from the eastern slope of the central Sahyadri across the
Deccan to the proximity of Bengaluru. The tanks
vary in area from 2 to >1,000 ha. Some of them
are <8 ha. Approx. 1,325 tanks are >50 ha. A few
are >500 ha in area. The climate is tropical monsoon. Temperature ranges from 11 to 43 °C.
20 Wetlands of India
population) indicated Microcystis sp. (68 %),
Phormidium sp. (55 %) and so on.
(g) Quality status: The water colour of many
lakes is sometimes greenish, indicating
eutrophication mainly due to algal
blooms. c 23 % of lakes are said to be
affected by eutrophication (Chakrapani and
Ramakrishna Parama 1996 ). Moreover,
there have been frequent fi sh kills in the
lakes mainly due to pollution (Benjamin
et al. 1996 ). Further, there have been human
health problems particularly due to not very
good quality of municipal water supplies.
This may be due to degraded water quality
problems in few tanks, like the
Kamakshipalya and Kempambudhi tanks.
Further, the degraded water may also be
affecting the lives of aquatic biota, notably
the birds, fi sh, etc. (Krishna et al. 1996 ).
Further, on a long-term basis, in addition to
the loss of habitat, recreational, aesthetic
and economic values, such degraded water
may affect the overall ecosystem diversity,
productivity and stability, including loss of
the capacity of the wetlands to assimilate
nutrients, purify water, etc.
(h) Turbidity usually varies from 1.0 to 362.0
NTU with cleaner water recording 1.0–25.0
NTU while polluted water recording 70.0–
362.0 NTU. The high value is mainly due to
silt, suspended and organic matter and
autochthonous sources. These retard the
penetration of light and reduce rate of photosynthesis (Kiran and Ramachandra 1999 ).
(i) The pH generally ranges from 7 to 9.3 in
urban areas and 7.3–8.7 in non-urban areas.
Notably, Kamakshipalya usually record pH
of 6.0–6.6 (Kiran et al . 1999 ). pH values
>9.0 may be recorded at Yediyur, Puttenahalli
and Ulsoor tanks (Chakrapani and
Ramakrishna Parama 1996 ).
(j) The COD values usually range from 27 mg/l
(in unpolluted waters) to 621 mg/l (in polluted waters like Kamakshipalya) (Kiran
and Ramachandra 1999 ).
(k) The DO values generally range from
1.2 mg/l (in Kamakshipalya Lake) to
11.1 mg/l (in Ulsoor and Yediyur Lakes)
(Kiran et al. 1999 ). However, the recommended DO concentration for a productive
lentic body is said to be 8 mg/l (Wetzel
1973 ).
(l) The phosphate level generally ranges from
0.06 to 4.2 mg/l. Higher values are generally
seen in Kamakshipalya Lake (Kiran and
Ramachandra 1999 ).
(m) The nitrate concentration in the Bengaluru
lakes usually ranges from 0.1 to 2.7 mg/l.
However, the standard level of nitrate for
inland surface water is generally 0.1 mg/l
(NEERI 1988 ; Kiran and Ramachandra
1999 ).
(n) Dissolved solids generally range from 30 to
301 mg/l (in less polluted lakes, like
Bannergatta and Sankey) to 430.0–
1,024.0 mg/l (in highly polluted lakes, such
as Kamakshipalya and Yediyur).
(o) Concomitantly, the suspended solids ranged
from 52.2 to 278.3 mg/l (Kiran and
Ramachandra 1999 ).
(p) Amongst the metals, high values of iron and
lead were noted, while zinc and chromium
were found in traces (Kiran et al. 1999 ). The
permissible limit for iron is said to be
0.3 mg/l (NEERI 1988 ) for drinking water.
Iron, possibly, imparts bitter taste to water
above this value (Chakrapani and
Ramakrishna Parama 1996 ).
(q) In fi ne, investigations revealed that most of
the analysed parameters for the lakes in
Bengaluru (e.g. Ulsoor, Hebbal, Yediyur,
Kamakshipalya and Madivala) depicted
higher values than the permissible limits set
by Indian Standards for industrial and sewage effl uents discharge (IS 2490–1982).
Tanks
These lie at 300–750 m MSL, between 12° 30′
and 15°00′ N and 75°00′ and 78° 00′ E on the
plains of Karnataka. They extend from the eastern slope of the central Sahyadri across the
Deccan to the proximity of Bengaluru. The tanks
vary in area from 2 to >1,000 ha. Some of them
are <8 ha. Approx. 1,325 tanks are >50 ha. A few
are >500 ha in area. The climate is tropical monsoon. Temperature ranges from 11 to 43 °C.
20 Wetlands of India